Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
cao hoc » co hoc, cho hoc, chat hoc
sach ty » sach y, sach tu, sach thu
hoc van » hoc dan, hoc va, hoc vat
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
ve cao » va cao, ve bao, ve cac
va cuu » va huu
va cau » van cau, va cac, va dau
va chu » va che, va chi

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ty nang xa hoi. hieu ve cao hoc van hanh ((((va cuu) OR (va cau))) or (va chu)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang xa hoi. hieu ve cao hoc van hanh ((((va cuu) OR (va cau))) OR (va chu)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang xa hoi. hieu ve cao hoc van hanh ((((va cuu) OR (va cau))) or (va chu)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang xa hoi. hieu ve cao hoc van hanh ((((va cuu) OR (va cau))) or (va chu)) tre*.